Objectives: To explore the clinical significance of squamous cell carcinoma antigen (SCC-Ag) and thrombocytosis to predict pelvic lymphatic metastasis (PLM) of squamous cervical cancer (SCC) in International Federation of Gynecology and Obstetrics (FIGO) stages IA-IIA. Methods: A retrospective clinicopathologic review of 782 patients of a primary cohort in three Chinese hospitals from 2010 to 2015, and 407 patients of a validation cohort in another institution from 2015 to 2017. A receiver operating characteristic curve was used to determine the optimal SCC-Ag threshold to predict PLM in the groups. Univariate and multivariate logistic analyses for PLM were performed to assess differences in outcome. Results: In the primary and validation cohort, 15.6% (122/782) and 25.3% (103/407) patients were classified into the thrombocytosis group (platelet count >300 x 10(9)/L), respectively. Optimal cutoff values of SCC-Ag for predicting PLM of the thrombocytosis group and the normal group were 3.26 ng/mL (AUC 0.754; sensitivity 73.08%; specificity 72.92%; P = 0.000) and 4.58 ng/mL (AUC 0.706; sensitivity 53.26%; specificity 83.98%; P = 0.000), respectively, in the primary cohort, and 1.55 ng/mL (AUC 0.705; sensitivity 79.31%; specificity 55.41%; P = 0.000) and 1.75 ng/mL (AUC 0.655; sensitivity 69.57%; specificity 64.26%; P = 0.000), respectively, in the validation cohort. In multivariate logistic analysis, preoperative SCC-Ag over 3.26 ng/mL and lymphovascular space involvement were the significant predictors of PLM for SCC in FIGO stages IA-IIA. Conclusions: Preoperative SCC-Ag alone or combined with thrombocytosis might be used as predictive markers for PLM before initial treatment in early stage SCC.